[CentOS] Centos-4.3: Filelocking problems under high [network related] load with kernel 2.6.9-42.0.3.ELsmp

Martin Knoblauch spamtrap at knobisoft.de
Mon Nov 27 18:54:34 UTC 2006


 first of all, please CC me on any reply, as I am only subscribed to
the digest.

OK. Here is the problem. Said kernel (from 4.4) seems to have problems
with file-locking when the system is under high, likely network
load. The symptoms are things using file locking (rpm, the user-space
automounter amd) fail to obtain locks, usually stating timeout

The sytem in question is a HP/DL380G4 with dual-single-core EM64T CPUs
and 8GB of Memory. The network interfaces are "tg3". It happens with
both CentOs and RHEL4.

The high load can be triggered by copying three 3 GB files in parallel
from an NFS server (Solaris10, NFS, TCP, 1GBit) to another NFS server
(RHEL4, NFS, TCP, 100 MBit). The measured network performance is OK.
During this operation the systems goes to Loads around/above 10.
Overall responsiveness feels good, but software doing file-locking or
stuff like opening a new ssh connection take extremely long.

So, if anyone has an idea or hint, it will be highly appreciated.


Martin Knoblauch
email: k n o b i AT knobisoft DOT de
www:   http://www.knobisoft.de

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